Abstract
Abstract. Frozen soil infiltration widely occurs in hydrological processes such as seasonal soil freezing and thawing, snowmelt infiltration, and runoff. Accurate measurement and simulation of parameters related to frozen soil infiltration processes are highly important for agricultural water management, environmental issues, and engineering problems in cold regions. Temperature changes cause soil pore size distribution variations and consequently dynamic infiltration capacity changes during different freeze–thaw periods. To better understand these complex processes and to reveal the freeze–thaw action effects on soil pore distribution and infiltration capacity, black soils, meadow soils, and chernozem were selected as test subjects. These soil types account for the largest arable land area in Heilongjiang Province, China. Laboratory tests of soils at different temperatures were conducted using a tension infiltrometer and ethylene glycol aqueous solution. The stable infiltration rate and hydraulic conductivity were measured, and the soil pore distribution was calculated. The results indicated that for the different soil types, macropores, which constituted approximately 0.1 % to 0.2 % of the soil volume under unfrozen conditions, contributed approximately 50 % of the saturated flow, and after soil freezing, the soil macropore proportion decreased to 0.05 % to 0.1 %, while the saturated flow proportion decreased to approximately 30 %. Soil moisture froze into ice crystals inside relatively large pores, resulting in numerous smaller-sized pores, which reduced the number of macropores but increased the number of smaller-sized mesopores, so that the frozen soil infiltration capacity was no longer solely dependent on the macropores. After the ice crystals had melted, more pores were formed within the soil, enhancing the soil permeability.
Highlights
Over the last few decades, the temperature changes caused by global warming have altered the freezing state of nearsurface soils, and in China, changes in characteristic values such as the extent of the mean annual area of the seasonal soil freeze–thaw state and maximum freezing depth indicate the degradation of frozen soil, especially at high latitudes (Wang et al, 2019; Peng et al, 2016)
The accurate measurement of water movement parameters and soil pore distribution under freeze–thaw conditions is a necessary prerequisite for the quantitative description of the water movement in frozen soil, and the mechanism and degree of influence of the temperature on the infiltration rate, hydraulic conductivity, porosity, and other parameters in the different stages of freeze–thaw periods require further research
Curves of the recorded cumulative infiltration and infiltration rate were plotted over time, as shown in Figs. 3 and 4, respectively
Summary
Over the last few decades, the temperature changes caused by global warming have altered the freezing state of nearsurface soils, and in China, changes in characteristic values such as the extent of the mean annual area of the seasonal soil freeze–thaw state and maximum freezing depth indicate the degradation of frozen soil, especially at high latitudes (Wang et al, 2019; Peng et al, 2016). Under the effect of temperature, most frozen regions experience seasonal freezing and thawing of soil, accompanied by coupled soil water and heat movement as well as frost heave processes, making the soil structure and function more variable (Oztas and Fayetorbay, 2003; Fu et al, 2019; Gao et al, 2018). Parameters such as the soil infiltration rate and hydraulic conductivity are key factors in the study of soil water movement, groundwater recharge, and solute and contaminant transport simulation (Angulo-Jaramillo et al, 2000). The accurate measurement of water movement parameters and soil pore distribution under freeze–thaw conditions is a necessary prerequisite for the quantitative description of the water movement in frozen soil, and the mechanism and degree of influence of the temperature on the infiltration rate, hydraulic conductivity, porosity, and other parameters in the different stages of freeze–thaw periods require further research
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
